package javax.annotation.concurrent;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/*
 * Copyright (c) 2005 Brian Goetz
 * Released under the Creative Commons Attribution License
 *   (http://creativecommons.org/licenses/by/2.5)
 * Official home: http://www.jcip.net
 */

/**
 * Immutable
 *
 * <p>The class to which this annotation is applied is immutable. This means that its state cannot
 * be seen to change by callers. Of necessity this means that all public fields are final, and that
 * all public final reference fields refer to other immutable objects, and that methods do not
 * publish references to any internal state which is mutable by implementation even if not by
 * design. Immutable objects may still have internal mutable state for purposes of performance
 * optimization; some state variables may be lazily computed, so long as they are computed from
 * immutable state and that callers cannot tell the difference.
 *
 * <p>Immutable objects are inherently thread-safe; they may be passed between threads or published
 * without synchronization.
 */
@Documented
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.CLASS)
public @interface Immutable {}
